/*
 * Copyright 2016 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package io.netty.example.http2.helloworld.multiplex.server;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http2.Http2SecurityUtil;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.ssl.ApplicationProtocolConfig;
import io.netty.handler.ssl.ApplicationProtocolConfig.Protocol;
import io.netty.handler.ssl.ApplicationProtocolConfig.SelectedListenerFailureBehavior;
import io.netty.handler.ssl.ApplicationProtocolConfig.SelectorFailureBehavior;
import io.netty.handler.ssl.ApplicationProtocolNames;
import io.netty.handler.ssl.OpenSsl;
import io.netty.handler.ssl.SslContext;
import io.netty.handler.ssl.SslContextBuilder;
import io.netty.handler.ssl.SslProvider;
import io.netty.handler.ssl.SupportedCipherSuiteFilter;
import io.netty.handler.ssl.util.SelfSignedCertificate;

/**
 * A HTTP/2 Server that responds to requests with a Hello World. Once started,
 * you can test the server with the example client.
 *
 * <p>
 * This example is making use of the "multiplexing" http2 API, where streams are
 * mapped to child Channels. This API is very experimental and incomplete.
 */
public final class Http2Server
{

    static final boolean SSL = System.getProperty("ssl") != null;

    static final int PORT = Integer
            .parseInt(System.getProperty("port", SSL ? "8443" : "8080"));

    public static void main(String[] args) throws Exception
    {
        // Configure SSL.
        final SslContext sslCtx;
        if (SSL)
        {
            SslProvider provider = OpenSsl.isAlpnSupported()
                    ? SslProvider.OPENSSL : SslProvider.JDK;
            SelfSignedCertificate ssc = new SelfSignedCertificate();
            sslCtx = SslContextBuilder
                    .forServer(ssc.certificate(), ssc.privateKey())
                    .sslProvider(provider)
                    /*
                     * NOTE: the cipher filter may not include all ciphers
                     * required by the HTTP/2 specification. Please refer to the
                     * HTTP/2 specification for cipher requirements.
                     */
                    .ciphers(Http2SecurityUtil.CIPHERS,
                            SupportedCipherSuiteFilter.INSTANCE)
                    .applicationProtocolConfig(
                            new ApplicationProtocolConfig(Protocol.ALPN,
                                    // NO_ADVERTISE is currently the only mode
                                    // supported by both OpenSsl and JDK
                                    // providers.
                                    SelectorFailureBehavior.NO_ADVERTISE,
                                    // ACCEPT is currently the only mode
                                    // supported by both OpenSsl and JDK
                                    // providers.
                                    SelectedListenerFailureBehavior.ACCEPT,
                                    ApplicationProtocolNames.HTTP_2,
                                    ApplicationProtocolNames.HTTP_1_1))
                    .build();
        }
        else
        {
            sslCtx = null;
        }
        // Configure the server.
        EventLoopGroup group = new NioEventLoopGroup();
        try
        {
            ServerBootstrap b = new ServerBootstrap();
            b.option(ChannelOption.SO_BACKLOG, 1024);
            b.group(group).channel(NioServerSocketChannel.class)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new Http2ServerInitializer(sslCtx));

            Channel ch = b.bind(PORT).sync().channel();

            System.err.println(
                    "Open your HTTP/2-enabled web browser and navigate to "
                            + (SSL ? "https" : "http") + "://127.0.0.1:" + PORT
                            + '/');

            ch.closeFuture().sync();
        }
        finally
        {
            group.shutdownGracefully();
        }
    }
}
